MID TERM REVIEW
Big Idea #1:
Earth Scientists use repeatable
observations and testable ideas to
understand and explain our planet
Big Idea #2:
Earth is a Water Planet
BIG IDEA #1:
Earth Scientists use repeatable observations and
testable ideas to understand and
explain our planet.
ENERGY THAT DRIVES EARTH’S 4-SYSTEMS
WHAT’S THE CONNECTION?
HOW DO SCIENTISTS THINK?




Critical thinking
Strong Observations
Extensive Documentation
Collaboration
CREDIBLE ONLINE SOURCES
DATA VS EVIDENCE
TURN DATA INTO EVIDENCE
factual information
 as measurements or statistics
 used as a basis for reasoning

• something that furnishes
proof
• something submitted to
ascertain the truth of a
matter.
TYPES OF DATA
Qualities VS Quantity
• Direct
SHOW ME THE EVIDENCE
• Indirect
•Modeling
HOW DO
AGE?
WE KNOW
EARTH
HAD AN ICE
EVIDENCE: DIRECT & INDIRECT
Earth’s interior

Direct Evidence: Rock Samples

Indirect Evidence :Seismic Waves
SCIENTIFIC MODELS
EXPLAINS SCIENTIFIC CONCEPTS
Accurate & Inaccurate
BIG IDEA #2
Earth is a Water Planet
WHY IS THIS IMPORTANT?
WHAT IS THE CONNECTION?
LETS TALK H2O VOCAB
Surface Tension
Salinity
Solvent
Capillary Action
THE SCIENCE OF WATER
WATER’S 7-UNUSUAL PROPERTIES
1. Stronger than normal bonds
2. High Surface Tension
3. High Boiling Temperatures
4. High Specific Heat
5. Universal Solvent
6. Density of the solid is less than at a liquid state
7. Adhesion, Cohesion, Capillary Action
FORMING A WATER MOLECULE
 Unequal
16
attraction to
bonding electrons
 Oxygen is a strong electron
grabber (high
electronegativity)
 Hydrogen’s electron tends to
hang out close to oxygen,
leaving H’s positively
charged
O+
O+
+
H-
+

WATER IS A POLAR MOLECULE
 Unequal
distribution of
charges on the water
molecule make it a
polar molecule
 One end is more
negative, and one
end is more positive
More positive ends
More negative end
+
means partial negative charge
means partial positive charge
ELECTRON DENSITY IS UNEVEN

Source: http://www.llnl.gov/str/October05/Mundy.html
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The electron density around
the oxygen atom in a water
molecule is about 10X greater
than the hydrogen atoms
 This non-uniform
distribution of positive
and negative charges,
called a dipole, leads to
Dark Blue= high density
H2O unusual behavior
Light Blue= low density
UNUSUAL PROPERTIES
LETS TALK OCEAN
WHERE
DOES THE SALT COME FROM?
WHAT INCREASES & DECREASES
SALINITY?
1. OCEAN LAYERS
FROM THE SHORE
1. OCEAN LAYERS
DEPTH: 3-ZONES
2. OCEAN VARIATIONS
Temperature: Thermocline
Density: Pycnocline
WATER ON A
GLOBAL PERSPECTIVE=
UNEQUAL HEATING
Longitude
Latitude
3. OCEAN CURRENTS
What drives them?
How do they form?
Effect of cold currents on climate?
What is the role in maintaining Earth’s heat balance?
2-Types: Density currents
Deep ocean currents
4. WAVES
WAVES TRANSFERS
ENERGY FROM ONE POINT TO
ANOTHER
5. TIDES
DAILY CHANGES IN THE ELEVATION OF THE OCEAN SURFACE